Hydraulic control system of an implement for a work machine and method thereof

ABSTRACT

An agricultural implement includes a transversely extending frame forming a first, a second, and a third frame section. A hydraulic control system controls a raising or lowering movement of each frame section. A first actuator and a second actuator are coupled to the first frame section, a third actuator is coupled to the second frame section, and a fourth actuator is coupled to the third frame section. A first control valve is fluidly coupled between a fluid source and the first and second actuators. A second control valve is fluidly coupled to the third actuator and a third control valve is fluidly coupled to the fourth actuator. A first flow path fluidly couples the first actuator, the second actuator, the third actuator, and the fourth actuator in series and a second flow path fluidly couples at least the third and fourth actuators in parallel with one another.

RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 15/058,745, filed Mar. 2, 2016, the disclosure of which ishereby incorporated by reference in its entirety.

FIELD OF THE DISCLOSURE

The present disclosure relates to a hydraulic control system, and inparticular to a hydraulic control system of an implement of a workmachine.

BACKGROUND OF THE DISCLOSURE

In the agricultural industry, wide implements such as field cultivatorsand the like include a main frame and adjacent outrigger or wing framesthat are hinged or pivotably coupled thereto. Each frame includes atleast one hydraulic actuator for raising or lowering the respectiveframe for proper depth control of tools. Conventional depth controlsystems utilize parallel or series hydraulic control. With series-onlycontrol, it can be difficult to provide individual depth control of eachframe section independently of the other frame sections. Withparallel-only control, more hydraulic flow is often required for raisingand lowering individual frame sections. Moreover, it can take longer toraise or lower the individual frame section with parallel-only flow.

In the present disclosure, a hydraulic depth control system is describedand illustrated for providing individual depth control of each framesection independently of the other frame sections and raise or lowereach frame section more quickly than conventional parallel-only controlsystems.

SUMMARY

In one embodiment of the present disclosure, an agricultural implementincludes a transversely extending frame forming at least a first framesection, a second frame section, and a third frame section, where thefirst frame section is disposed between the second and third framesections; a hitch member configured to couple to a work machine, thehitch member being coupled to at least one of the first, second, andthird frame sections; and a hydraulic control system for controlling araising or lowering movement of the frame, the system including a firstactuator and a second actuator coupled to the first frame section, athird actuator coupled to the second frame section, and a fourthactuator coupled to the third frame section; a fluid source forproviding hydraulic fluid; a first control valve operably controllablebetween an open position and a closed position, the first control valvebeing fluidly coupled between the fluid source and the first and secondactuators; a second control valve operably controllable between an openposition and a closed position, the second control valve being fluidlycoupled to the third actuator in its open position; a third controlvalve operably controllable between an open position and a closedposition, the third control valve being fluidly coupled to the fourthactuator in its open position; a first flow path defined between thefluid source and the third and fourth actuators, the first flow pathfluidly coupling the first actuator, the second actuator, the thirdactuator, and the fourth actuator in series with one another when thefirst control valve is in its open position, the second control valve isin its closed position, and the third control valve is in its closedposition; and a second flow path defined between the fluid source andthe third and fourth actuators, the second flow path fluidly coupling atleast the third and fourth actuators in parallel with one another whenthe first control valve is in its closed position, and either the secondcontrol valve or the third control valve is in its open position.

In one example of this embodiment, the implement may include a fluidreservoir; and a third flow path fluidly coupling the third actuator andthe fourth actuator to the fluid reservoir. In a second example, thehydraulic control system includes a first node fluidly coupling thefirst and second flow paths to one another; a second node fluidlycoupling the first control valve, the first actuator and the secondactuator to one another; a third node fluidly coupling the first fluidpath, the second fluid path, the second control valve and the thirdactuator to one another; and a fourth node fluidly coupling the firstfluid path, the second fluid path, the third control valve, and thefourth actuator to one another. In a third example, the first controlvalve is an electrohydraulic control valve biased in its open position,the second control valve is an electrohydraulic control valve biased inits closed position, and the third control valve is an electrohydrauliccontrol valve biased in its closed position.

In a fourth example of this embodiment, an electronic control unit maybe coupled to the frame for controlling the first, second and thirdcontrol valves between their respective open and closed positions. In afifth example, a first sensor is disposed in electrical communicationwith the electronic control unit, the first sensor detecting a positionof the first frame section; a second sensor is disposed in electricalcommunication with the electronic control unit, the second sensordetecting a position of the second frame section; and a third sensor isdisposed in electrical communication with the electronic control unit,the third sensor detecting a position of the third frame section. In asixth example, each frame section includes a plurality of tools forpenetrating a soil upon which the implement travels; wherein, each ofthe first, second, and third sensor operably detects a depth ofpenetration of the plurality of tools coupled to each frame section andcommunicates the detected depth to the electronic control unit, theelectronic control unit compares the detected depth to a target depthand operably controls the position of each control valve until the depthof the plurality of tools on each frame section is at the target depth.

In a seventh example of this embodiment, when the depth of the pluralityof tools coupled to the second frame section or the third frame sectionis not at the target depth, the electronic control unit operablycontrols fluid flow through the third or fourth actuator via the secondflow path until the depth is detected at the target depth. In an eighthexample, the agricultural implement may include a fourth frame sectioncoupled to the second frame section, the fourth frame section includinga fifth actuator for controlling a raising or lowering movement of thefourth frame section; a fifth frame section coupled to the third framesection, the fifth frame section including a sixth actuator forcontrolling a raising or lowering movement of the fifth frame section; afourth control valve operably controllable between an open position anda closed position, the fourth control valve being fluidly coupled to thefifth actuator in its open position; and a fifth control valve operablycontrollable between an open position and a closed position, the fifthcontrol valve being fluidly coupled to the sixth actuator in its openposition; wherein, the first flow path fluidly couples the first,second, third, fourth, fifth, and sixth actuators in series with oneanother when only the first control valve is in its open position, andthe second flow path fluidly couples the third, fourth, fifth, and sixthactuators in parallel with one another when the first control valve isin its closed position.

In another example of this embodiment, a plurality of tools is coupledto each frame section; and a plurality of sensors for detecting a depthat which the plurality of tools coupled to each frame section penetratesa soil upon which the implement travels along; wherein, when the depthof the plurality of tools coupled to either the second frame section orthe third frame section is not at a target depth, the electronic controlunit operably controls the first control valve to its closed positionand either the second or third control valve to its open position sothat hydraulic fluid from the fluid source flows through the second flowpath to either the third or fourth actuator to raise or lower the secondor third frame section until the depth of the first frame section, thesecond frame section and the third frame section are at the targetdepth. In a further example of this embodiment, once the depth of thesecond frame second or the third frame section is operably controlled tothe target depth, the electronic control unit operably controls thefirst control valve to remain in its closed position, the second andthird control valves are controlled to their respective closedpositions, and either the fourth or fifth control valve is operablycontrolled to its open position so that hydraulic fluid from the fluidsource flows through the second flow path to either the fifth or sixthactuator to raise or lower the fourth or fifth frame section until thedepth of the first frame section, the second frame section, the thirdframe section, the fourth frame section, and the fifth frame section areat the target depth.

In another embodiment of the present disclosure, a work machine includesa frame; a controller for controlling the machine; a fluid source forproviding hydraulic fluid; a work implement coupled to the frame forperforming a work function, the work implementing including atransversely extending frame forming at least a first frame section, asecond frame section, and a third frame section, where the first framesection is disposed between the second and third frame sections; aplurality of work tools coupled to each of the first, second, and thirdframe sections; an electronic control system for electronicallycontrolling the implement, the electronic control system including anelectronic control unit (ECU) and a plurality of sensors, where the ECUis disposed in communication with the controller and the plurality ofsensors are configured to detect a depth of penetration of the pluralityof work tools into a ground surface upon which the implement travels,each of the plurality of sensors disposed in electrical communicationwith the ECU; and a hydraulic control system for hydraulicallycontrolling a raising or lowering movement of each frame section, thehydraulic control system including a first actuator coupled to the firstframe section, a second actuator coupled to the second frame section,and a third actuator coupled to the third frame section; a first controlvalve operably controllable between an open position and a closedposition, the first control valve being fluidly coupled between thefluid source and the first actuator; a second control valve operablycontrollable between an open position and a closed position, the secondcontrol valve being fluidly coupled to the second actuator in its openposition; a third control valve operably controllable between an openposition and a closed position, the third control valve being fluidlycoupled to the third actuator in its open position; a first flow pathdefined between the fluid source and the second and third actuators, thefirst flow path fluidly coupling the first actuator, the secondactuator, and the third actuator in series with one another when thefirst control valve is in its open position, the second control valve isin its closed position, and the third control valve is in its closedposition; and a second flow path defined between the fluid source andthe second and third actuators, the second flow path fluidly coupling atleast the second and third actuators in parallel with one another whenthe first control valve is in its closed position, and either the secondcontrol valve or the third control valve is in its open position.

In one example of this embodiment, the work machine may include a fluidreservoir fluidly coupled to the fluid source; and a third flow pathfluidly coupling the second actuator and the third actuator to the fluidreservoir. In another example, the implement may include a fourth framesection coupled to the second frame section, the fourth frame sectionincluding a fourth actuator for controlling a raising or loweringmovement of the fourth frame section; and a fifth frame section coupledto the third frame section, the fifth frame section including a fifthactuator for controlling a raising or lowering movement of the fifthframe section; a fourth control valve operably controllable by the ECUbetween an open position and a closed position, the fourth control valvebeing fluidly coupled to the fourth actuator in its open position; and afifth control valve operably controllable by the ECU between an openposition and a closed position, the fifth control valve being fluidlycoupled to the fifth actuator in its open position; wherein, the firstflow path fluidly couples the first, second, third, fourth, and fifthactuators in series with one another when only the first control valveis in its open position, and the second flow path fluidly couples thesecond, third, fourth, and fifth actuators in parallel with one anotherwhen the first control valve is in its closed position.

In a further embodiment of the present disclosure, a method is providedfor controlling an agricultural implement having a transverselyextending frame forming a center frame section, a first frame sectiondisposed on one side of the center frame section, and a second framesection disposed on an opposite side of the center frame section, themethod including providing a fluid source, an electronic control unit, afirst control valve, a second control valve, a third control valve, afirst and a second actuator coupled to the center frame section, a thirdactuator coupled to the first frame section, a fourth actuator coupledto the second frame section, and a plurality of tools coupled to eachframe section; providing a first fluid path and a second fluid path, thefirst fluid path fluidly coupling the first, second, third and fourthactuators in series when the first control valve is open, and the secondfluid path fluidly coupling the third and fourth actuators in parallelwith one another when the first control valve is closed; operating theagricultural implement in a working position, where in the workingposition each of the plurality of tools is disposed at a target depth ina ground surface upon which the implement travels; detecting a depthposition of the plurality of tools coupled to the center frame sectionwith a first sensor, a depth position of the plurality of tools coupledto the first frame section with a second sensor, and a depth position ofthe plurality of tools coupled to the second frame section with a thirdsensor; communicating the depth position of the plurality of tools tothe electronic control unit; determining if the depth position of theplurality of tools is at the target depth; wherein, when the depthposition of the plurality of tools coupled to the center frame section,the first frame section, or the second frame section is not at thetarget depth, the method further includes controllably opening the firstcontrol valve and closing the second and third control valves to raiseor lower the center frame section until the depth of the plurality oftools coupled to the center frame section is at the target depth; andcontrollably closing the first control valve and opening the second orthird control valve to raise or lower either the first or section framesection until the depth of the plurality of tools coupled to the firstor second frame section is at the target depth.

In one example of this embodiment, the method may include controllingfluid flow through the first fluid path to raise or lower the centerframe section, the first frame section and the second frame section. Ina second example, the method may include controlling fluid flow throughthe first and second actuators to position the frame between a transportposition and its working position. In a third example, the method mayinclude controlling fluid flow through the second fluid path to controlthe depth of the plurality of tools coupled to one of the first orsecond frame sections; and blocking fluid flow through the first flowpath to the first and second actuators.

In another example of this embodiment, the method may include providinga third frame section coupled to the first frame section, a fourth framesection coupled to the second frame section, a fourth control valve, afifth control valve, a fifth actuator, and a sixth actuator, where thefifth actuator and sixth actuator are fluidly coupled in series to thefirst actuator, second actuator, third actuator and fourth actuator viathe first flow path, and the fifth actuator and sixth actuator arefluidly coupled in parallel with the third actuator and the fourthactuator via the second flow path; providing a plurality of toolscoupled to the third frame section and the fourth frame section;detecting the plurality of tools coupled to either the third framesection or the fourth frame section is not at the target depth;controllably closing the first control valve and the first flow path;controllably opening the fourth or the fifth control valve; and fluidlycoupling the fluid source to the fifth or sixth actuator to raise orlower the third frame section or the fourth frame section until theplurality of tools coupled to the third frame section and fourth framesection are at the target depth.

In yet another example of this embodiment, the method may includeproviding a third frame section coupled to the first frame section, afourth frame section coupled to the second frame section, a fourthcontrol valve, a fifth control valve, a fifth actuator, and a sixthactuator, where the fifth actuator and sixth actuator are fluidlycoupled in series to the first actuator, second actuator, third actuatorand fourth actuator via the first flow path, and the fifth actuator andsixth actuator are fluidly coupled in parallel with the third actuatorand the fourth actuator via the second flow path; providing a pluralityof tools coupled to the third frame section and the fourth framesection; detecting the plurality of tools coupled to the first framesection or the second frame section is not at the target depth;controllably closing the first control valve; controllably opening thesecond control valve or the third control valve depending upon whetherthe depth of the plurality of tools coupled to the first or second framesections is not at the target depth; fluidly coupling the fluid sourceto the third actuator or the fourth actuator to raise or lower the firstor the second frame section until the plurality of tools coupled to thefirst and second frame sections are at the target depth; furtherdetecting the depth of the plurality of tools coupled to either thethird frame section or the fourth frame section is not at the targetdepth; controllably maintaining the first control valve in its closedposition;

controllably closing the second or third control valve; controllablyopening the fourth or fifth control valve; and fluidly coupling thefluid source to the fifth or sixth actuator to raise or lower the thirdframe section or the fourth frame section until the plurality of toolscoupled to the third frame section and fourth frame section are at thetarget depth.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned aspects of the present disclosure and the manner ofobtaining them will become more apparent and the disclosure itself willbe better understood by reference to the following description of theembodiments of the disclosure, taken in conjunction with theaccompanying drawings, wherein:

FIG. 1 is an elevated view of an agricultural implement;

FIG. 2 is a diagram of an electronic control system of a work machineand the agricultural implement of FIG. 1;

FIG. 3 is a diagram of a hydraulic control system of the work machineand agricultural implement of FIG. 2;

FIG. 4 is a chart of valve and cylinder primary response for tool depthcontrol;

FIG. 5 is a chart of valve and cylinder secondary response for tooldepth control;

FIG. 6 is an elevated view of another agricultural implement;

FIG. 7 is an elevated view of an air seeder; and

FIG. 8 is a side view of the air seeder of FIG. 7.

Corresponding reference numerals are used to indicate correspondingparts throughout the several views.

DETAILED DESCRIPTION

The embodiments of the present disclosure described below are notintended to be exhaustive or to limit the disclosure to the preciseforms in the following detailed description. Rather, the embodiments arechosen and described so that others skilled in the art may appreciateand understand the principles and practices of the present disclosure.

Referring to FIG. 1, an agricultural implement 100 such as a fieldcultivator is shown. The implement 100 is designed to couple to a workmachine and perform a work function. For example, the implement mayinclude work tools that penetrate into soil for aerating the soil beforeplanting or uprooting weeds after planting. The implement 100 may beattached to a work machine or tractor (not shown) by a hitch assembly112 such as a three-point hitch or a drawbar attachment. The hitchassembly 112 includes a hitch frame member 114 that extendslongitudinally in a direction of travel for coupling to the work machineor tractor.

The agricultural implement 100 may include a transversely-extendingframe that forms multiple frame sections. In FIG. 1, for example, theimplement 100 includes a main or center frame 102. The main frame 102 iscoupled to the hitch assembly 112 as shown. A first frame section orfirst inner frame 104 is disposed to one side of the main frame 102, anda second frame section or second inner frame 106 is disposed to anopposite side thereof. In addition, a third frame section or first outerframe 108 is disposed to an outside of the first inner frame 104, and afourth frame section or second outer frame 110 is disposed to an outsideof the second inner frame 106. Each frame section may be pivotablycoupled to the frame section adjacent thereto. The first inner frame104, for example, may be pivotably coupled to the main frame 102 and thefirst outer frame 108. Similarly, the second inner frame 106 may bepivotably coupled to the main frame 102 and the second outer frame 110.

The implement 100 may be supported by a plurality of wheels. Forexample, a pair of front wheels 116 are coupled to the frame at a frontend thereof. The main frame 102 may be supported by a first pair ofwheels 118 and a second pair of wheels 120. The first inner frame 104may be supported by a third pair of wheels 130 and the second innerframe 106 may be supported by a fourth pair of wheels 136. Likewise, thefirst outer frame 108 may be supported by a fifth pair of wheels 142 andthe second outer frame 110 may be supported by a sixth pair of wheels148. While each section is shown being supported by a different pair ofwheels, this is only shown in the illustrated embodiment. In otherembodiments, there may be only a single wheel supporting each framesection. In a different embodiment, there may be more than a pair ofwheels supporting each frame section. Moreover, the implement 100 mayinclude more than the front wheels 116. For instance, there may be backwheels disposed near the rear of the implement for additional support.

In the illustrated embodiment of FIG. 1, the agricultural implement 100may include a plurality of actuators for controlling movement of theframe. Each actuator may be a hydraulic actuator, electric actuator, orany other known actuator. Moreover, each actuator may include an outerbody or cylinder in which a rod or piston moves between an extendedposition and a retracted position. In FIG. 1, the main frame 102includes a first actuator 122 and a second actuator 124. The first pairof wheels 118 may be coupled to the main frame 102 via a rock shaft (notshown) that may be hydraulically actuated by the first actuator 122. Thesecond pair of wheels 120 may be coupled to the main frame 102 viaanother rock shaft (not shown) that may be hydraulically actuated by thesecond actuator 124. The actuators can raise or lower the main frame 102relative to the wheels 118, 120, as will be described below.

The first inner frame 104 may include an actuator 132 for raising orlowering the first inner frame 104. Similarly, the second inner frame106 may include an actuator 138 for controlling a raising or loweringmovement of the second inner frame 104. The first outer frame 108 mayinclude an actuator 144 and the second outer frame 110 may include anactuator 150. The actuator 144 may control raising and lowering of thefirst outer frame 108 and the actuator 150 may control raising andlowering of the second outer frame 110.

In FIG. 1, the main frame 102 includes a plurality of main frame members126. A plurality of tools 152 may be coupled to the main frame members126 for engaging a ground surface or soil upon which the implementtravels. Similarly, the first inner frame 104 includes a plurality offirst inner frame members 128, the second inner frame 106 includes aplurality of second inner frame members 134, the first outer frame 108includes a plurality of first outer frame members 140, and the secondouter frame 110 includes a plurality of second outer frame members 146.Each of these frame members may include a plurality of work tools 152coupled thereto.

While FIG. 1 represents an illustrated embodiment of an agriculturalimplement with five frame sections, this disclosure is not limited tothis embodiment. Other embodiments may include only three sections witha main frame and two outer frames. Alternatively, there may be more thanfive frame sections in further embodiments. Thus, this disclosure is notlimited to any number of frame sections, and the teachings herein may beapplicable to any multi-section implement.

Referring to FIG. 2, an electronic control system 200 is shown of anagricultural implement 204 similar to the one described above and shownin FIG. 1. Where applicable, reference numbers are repeated in FIG. 2 asfirst addressed above with reference to FIG. 1. In FIG. 2, a workmachine 202 and the implement 204 are shown. The work machine 202 mayinclude a frame or chassis 202 supported by a plurality ofground-engaging mechanisms (not shown) such as wheels. An operator's cab(not shown) may be mounted to the frame and an operator may control thework machine 202 therefrom. To do so, the work machine 202 may include aplurality of controls (not shown) such as joysticks, levers, switches,knobs, a steering wheel, pedals, and the like. A controller 206 may beelectrically coupled to the plurality of controls, and the controller206 may control the functionality of the work machine 202.

Moreover, a user interface 208 may be disposed in the operator's cab.The user interface 208 may include a display 210 for displaying variouscharacteristics of the work machine such as, but not limited to, speed,fluid temperatures, fluid pressures, direction of travel, etc. Thedisplay 210 may be a touchscreen display that allows the operator tocontrol certain functions of the machine 202 by touching a button on thedisplay 210. Other uses of the user interface are available and thisdisclosure is not intended to be limited in any way with respect to thefunctionality of the operator controls or user interface 208.

The user interface 208 may also include controls for controlling theimplement 204, such as movement of the frame or setting a tool depth.For example, the operator may desire to raise or lower the main frame102 of the implement. To do so, the operator may input an instructionthrough the user display 208 which is received by the controller 206.The controller 206 may communicate with an electronic control unit (ECU)212 of the implement 204 via a wireless or control area network (CAN)214. A CAN is a vehicle bus standard designed to allow microcomputersand other electronic devices to communicate electronically with eachother in applications without a host computer. Here, the machinecontroller 206 may send an instruction to the implement ECU 212 to raiseor lower the main frame 102. As will be described, the ECU 212 may beprogrammed to execute this instruction and raise or lower the main frame102 or any other frame section of the implement.

Referring to FIGS. 1 and 2, the ECU 212 may be in electricalcommunication with a plurality of sensors (e.g., rotary, Hall Effect)that are disposed at various locations on the implement 204. Forinstance, a first sensor 216 may be disposed at a location on the mainframe 102 for detecting rotation of the rock shaft (not shown) which isconnected to the first pair of wheels 118. A second sensor 218 may bedisposed at a location on the main frame 102 for detecting rotation ofthe rock shaft connected to the second pair of wheels 120. Each sensormay be a rotary sensor, a Hall Effect sensor, or any other type ofsensor. In addition, the first and second sensors may detect rotation ofthe rock shafts and communicate accordingly to the ECU 212. The ECU inturn can adjust or set the height of the main frame 102.

For example, a height of the wheels can be used to set a frame height.As described above, a plurality of ground-engaging work tools 152 may becoupled to the main frame 102. By controlling or actuating the firstactuator 122 and the second actuator 124, the height of the main frame102 can change for setting a depth of the work tools 152 into a groundsurface or soil upon which the implement 100 travels. The first sensor216 and the second sensor 218 may be positioned appropriately to detectrotation of the rock shaft. As the rock shaft rotates, the actuatorextends or retracts. The ECU 212 may be programmed such that when thefirst actuator 122 and second actuator 124 are fully extended the mainframe height is at a first height, and when the actuators are fullyretracted the main frame height is at a second height. As the actuatorcylinders extend and retract, the first pair of wheels 118 and secondpair of wheels 120 can be raised or lowered, thereby adjusting theheight of the main frame 102.

Besides the sensors on the main frame, a third sensor 222 may bedisposed on the first inner frame 104 and detect a height of the thirdpair of wheels 130. A fourth sensor 226 may be disposed on or near thesecond inner frame 106 for detecting a height of the fourth pair ofwheels 136. A fifth sensor 230 may be disposed on or near the firstouter frame 108 for detecting a height of the fifth pair of wheels 142.Likewise, a sixth sensor 234 may be disposed on or near the second outerframe 110 for detecting a height of the sixth pair of wheels 148. Eachof the third, fourth, fifth, and sixth sensors may be in electricalcommunication with the ECU 212. Moreover, while six different sensorsare shown in FIG. 2, the present disclosure is not limited to sixsensors. Other embodiments may include additional sensors for detectingand setting frame height. For those embodiments with fewer framesections, there may be fewer sensors. Each sensor detects a position ofwheels on each frame section, and thus the number of sensors may dependon the number of frame sections of a multi-section implement.

Referring to FIGS. 2 and 3, the implement 204 may also include aplurality of control valves for controlling movement of the overallframe and each independent frame section. As shown, a first controlvalve 220 may be in electrical communication with the ECU 212. The firstcontrol valve 220 may be used for adjusting the height of the overallframe or only the main frame 102. A second control valve 224 may be inelectrical communication with the ECU 212 for controlling a raising orlowering movement of the first inner frame 104. A third control valve228 may be in electrical communication with the ECU 212 for controllinga raising or lowering movement of the second inner frame 106. A fourthcontrol valve 232 may be in electrical communication with the ECU 212for controlling a raising or lowering movement of the first outer frame108. Moreover, a fifth control valve 236 may be in electricalcommunication with the ECU 212 for controlling a raising or loweringmovement of the second outer frame 110.

Each of the aforementioned control valves may be an electrohydrauliccontrol valve that is capable of moving between an open position and aclosed position. Each valve may include a solenoid (not shown) that isenergized by an electrical current or signal sent by the ECU 212 toinduce movement of the valve between the open and closed positions. Themovement of the control valves can adjust fluid flow to the differentactuators for controlling movement of the overall frame or eachindividual frame section, as will be described below.

Among other things, the present disclosure provides details of ahydraulic control system for achieving depth control of work tools andcontrolling movement of a multi-section frame of an agriculturalimplement. With multi-section frame implements such as the one shown inFIG. 1, it is desirable to achieve uniform tool depth along eachsection. Each section may have different tolerances or there may be asmall leak in the actuator that controls movement of an individual framesection. In either case, it can be difficult to achieve uniform depthacross each frame section and therefore the implement can utilize itshydraulic control system (and other control systems) to monitor andmaintain uniform depth control.

In conventional hydraulic control systems, the two most common types ofdepth control systems are series hydraulic control and parallelhydraulic control. A series hydraulic control is typically a puremechanical system without any electronic control. Here, hydraulic fluidis supplied from a fluid source to a first or master actuator orcylinder. The master cylinder receives the full amount of fluid flow,and as the master cylinder is actuated, fluid is displaced from themaster cylinder and flows to the next-in-line actuator or cylinder. Inthis system, each actuator or cylinder is fluidly connected to oneanother in a series which allows for each cylinder to quickly receivefluid from the fluid source.

The series hydraulic control is ideal when it is necessary to raise theentire implement frame. However, it is not as desirable when only oneframe section needs to be raised or lowered. As a result, someimplements utilize the parallel hydraulic control. The parallelhydraulic control can include electronic control unlike the serieshydraulic control. In this type of control, valves are utilized tocontrol how fluid flows through the system. Fluid flows across eachsection in an equal amount so that fluid is available at each wheel toadjust a frame section height. The fluid source, however, only has alimited amount of fluid. Thus, when an operator wants to raise or lowera certain frame section, the parallel hydraulic control is capable ofproviding fluid to the actuator at that section but it may take muchlonger than in a series hydraulic control. It therefore can take longerto raise or lower a frame section, which can delay the operator fromperforming a desired function or operation. A slower system response isoften the result with a depth control system consisting of conventionalparallel hydraulic control.

Referring to FIG. 3, the present disclosure provides a different type ofdepth control system for the implement 204. Here, a combination of theseries hydraulic control and parallel hydraulic control form a hybridparallel-series hydraulic depth control system 300. In this system 300,additional hydraulics is added to obtain the benefits of both the seriesand parallel control while eliminating or reducing the problemsassociated with each. In FIG. 3, a fluid source 302 provides hydraulicfluid to the system 300. The fluid source 302 may be located on the workmachine or tractor 202, and a hydraulic pump may supply the fluid to theimplement. A fluid reservoir or tank 304 may also be provided for fluidto return from the implement 204. The fluid source 302 and fluidreservoir 304 may be fluidly coupled to one another.

The work machine or tractor 202 may also include a selective controlvalve 306 that is fluidly coupled to the fluid source 302. The valve 306may be any type of valve that selectively allows fluid to flow from thework machine 202 to the implement 204. The valve 306 may be anelectrohydraulic control valve that is controlled by the machinecontroller 206. For example, the controller 206 may be programmed toselectively open and close the control valve 206. If the work machine202 requires additional hydraulic fluid to perform an operation, thecontroller 206 may close the valve 306 and not permit fluid to flow tothe implement 204. In one embodiment, the selective control valve 306may be biased to its open position and thus may be referred to as anormally open control valve. In another embodiment, the valve 306 may bebiased to its closed position and thus be referred to as a normallyclosed valve.

In any event, hydraulic fluid may be supplied by the fluid source 302through the control valve 306 and to the implement 204 via a first flowpath 308 or pressure line. The first flow path 308 may be defined suchthat is passes through the first control valve 220 and to each of thefirst actuator 122 and second actuator 124. Moreover, when the first orsecond actuator is actuated, fluid displacement may result in fluidflowing through the first flow path to either the third actuator 132 orfourth actuator 138. Similarly, when either the third or fourth actuatorare actuated, the fluid displacement in the actuator may allow fluid toflow to the fifth actuator 144 or sixth actuator 150 via the first flowpath 308. In this embodiment, the first flow path 308 forms a serieshydraulic control in which each actuator is fluidly coupled to oneanother in series. This can allow an operator to raise or lower theentire frame of the implement 204, or raise or lower the main frame 102.

In the first fluid path 308 or pressure line, the first control valve220 may be biased in its open position. In this embodiment, the firstcontrol valve 220 is a normally open electrohydraulic control valve andthus hydraulic fluid can flow via the first fluid path 308 through thefirst control valve 220 without requiring any interaction by the ECU212. This again is similar to the series hydraulic control describedabove. In this disclosure, however, it is appreciated that in otherembodiments, the first control valve 220 may be a normally closedelectrohydraulic control valve. In these other embodiments therefore theECU 212 may be required to actuate or trigger the valve to its openposition. In a further embodiment, the first control valve 220 may notbe controlled by the ECU 212 or biased in either an open or closedposition, but rather pressure acting on either side of the valve mayactuate it between an open and closed position. Thus, different types ofvalves may be used in the embodiments described herein.

To control depth of the plurality of work tools 152, a second fluid path310 or pressure line may be provided. A node 314 may be provided wherethe first and second fluid paths intersect. The node 314 may be amanifold or T that allows fluid to flow through both lines. Thus, fluidcan flow from the fluid source 302 through the first fluid path 308 andthe second fluid path 310. As shown in FIG. 3, however, the secondcontrol valve 224, the third control valve 228, the fourth control valve232, and the fifth control valve 236 may be biased in their closedpositions. Thus, fluid flowing through the second flow path is unable toflow through these other control valves until the ECU 212 selectivelyopens one of the control valves. If the ECU 212 selectively opens thesecond control valve 224, for example, then fluid can flow through thevalve 224 via the second flow path 310 and reach the third actuator 132.In doing so, the third actuator 132 may be controllably actuated toraise or lower the first inner frame 104 to adjust the depth of itsplurality of work tools 152.

Similar to the first control valve 220 described above, this disclosureis not intended to limit the different control valves to any particularbiased position. Thus, the second control valve 224, the third controlvalve 228, the fourth control valve 232, and the fifth control valve 236may be biased or pre-disposed in a normally open position or a normallyclosed position. Alternatively, these control valves may be actuated byfluid pressure acting on either side of each respective valve, therebynot requiring intervention by the ECU 212. Other embodiments thatincorporate any type of valve may be used to achieve the operation ofthe control system 300.

The control system 300 may also include a third fluid path 312 or returnpressure line. Each actuator may be designed to include at least twodifferent fluid ports. One port may be disposed on a base side of theactuator and the other port may be disposed on a rod side of theactuator. The third fluid path 312 is fluidly coupled to the fluidreservoir 304, the fifth actuator 144, and the sixth actuator 150. Anyfluid that flows through the first and second flow paths can thereforebe returned to the reservoir 304 via the third flow path 312. As aresult, a combination of the first and third flow paths and the secondand third flow paths can define a closed-loop hydraulic circuit.

As previously described, the first control valve 220 does not requireany electronic intervention or control by the ECU 212 to permit fluidflow through the series portion of the system 300. On the other hand,the second control valve 224, the third control valve 228, the fourthcontrol valve 232, and the fifth control valve 236 are electricallycontrolled by the ECU 212 to permit fluid flow through the parallelportion of the system 300. When an operator commands a raising orlowering movement of an individual frame section, the ECU 212 maycommand the first control valve 220 to its closed position and open oneof the normally-closed valves to allow fluid flow through the secondflow path 310 to the appropriate actuator for raising or lowering thedesired frame section. This type of control will be described withreference to FIGS. 4 and 5.

Before turning to FIGS. 4 and 5, however, the hydraulic control system300 of FIG. 3 includes a plurality of nodes or manifolds. As previouslydescribed, the first node 314 is an intersection point of the first andsecond flow paths. A second node 316 may be disposed in the first fluidpath 308 downstream of the first control valve 220. Here, the first flowpath 308 separates into two flow paths so that fluid can be supplied tothe first actuator 122 along one path and the second actuator 124 alonga second path.

A third node is another intersection point of the first and second flowpaths, but it is located downstream of the second control valve 224.Here, fluid may pass through the third node 318 and to the thirdactuator 132. A fourth node 320 is an intersection point of the firstand second fluid paths, but it is located downstream of the thirdcontrol valve 228 and upstream from the fourth actuator 138. A fifthnode 322 is another intersection point of the first and second flowpaths, but it is located downstream of the fourth control valve 232 andupstream from the fifth actuator 144. Lastly, a sixth node 324 providesa further intersection point of the first and second flow paths, but itis located downstream from the fifth control valve 236 and upstream ofthe sixth actuator 150. In the illustrated embodiment, each of thethird, fourth, fifth and sixth nodes are located between a differentcontrol valve and a different actuator. Unlike the first and secondnodes, however, fluid may only flow through either the first or secondflow path when passing through each of the third, fourth, fifth andsixth nodes due to the ECU selectively opening or closing the differentcontrol valves.

Referring to FIG. 4, control logic for controlling the implement isprovided. Here, the logic includes a primary control valve responsetable 400 and a primary actuator or cylinder response table 402. In thevalve response table 400, there are rows that refer to a type ofresponse commanded by an operator such as raise or lower the overallimplement frame (e.g., “Raise Overall”), raise or lower the main frame102 (e.g., “Raise MF”), raise or lower the first inner frame 104 (e.g.,“Raise LIW”), raise or lower the second inner frame 106 (e.g., “RaiseRIW”), raise or lower the first outer frame 108 (e.g., “Raise LOW”), andraise or lower the second outer frame 110 (e.g., “Raise ROW”). In thistable, “R” refers to right and “L” refers to left when looking at theimplement from its front rearward. Moreover, “I” refers to inner and “O”refers to outer.

The other rows in the valve response table 400 indicate the differentframe sections of the implement. Here, “RMF” and “LMF” refer to rightmain frame and left main frame, respectively. In FIG. 1, this is simplythe main frame 102. “LIW” and “RIW” refer to left inner wing and rightinner wing, respectively. The left inner wing is the first inner frame104 and the right inner wing is the second inner frame 106 as shown inFIG. 1. Further, “LOW” and “ROW” refer to left outer wing and rightouter wing, respectively, which corresponds with the first outer frame108 and the second outer frame 110, respectively. In this table 400, theresponse of each control valve is illustrated as either being in itsopen position “O” or closed position “C”.

For purposes of table 400, the first control valve 220 has a responseindicated with reference number 404, the second control valve 224 has aresponse indicated as reference number 408, the third control valve 228has a response indicated as reference number 406, the fourth controlvalve 232 has a response indicated as reference number 412, and thefifth control valve 236 has a response indicated as reference number410.

In the primary actuator or cylinder table 402, the rows and columns aresimilar to those in table 400. Here, however, the actuator is beingcharacterized as either being in its extended position “E” or itsretracted position “R”. In the event the actuator is not actuated, thenneither an “E” or an “R” appears in the respective box. The response ofthe first and second actuators is represented by reference number 414.The response of the third actuator 132 is represented by referencenumber 418, the response of the fourth actuator 138 is represented byreference number 416, the response of the fifth actuator 144 isrepresented by reference number 422, and the response of the sixthactuator 150 is represented by reference number 420 in FIG. 4.

Referring to FIG. 5, the control logic for controlling the implement mayalso include a secondary control valve response table 500 and asecondary actuator or cylinder response table 502. In the secondaryvalve response table 500, a first column 504 provides for differentresponses or reactions required of the different control valves. Here,if a secondary response is required, the column 504 illustrates a “Y”,and if no secondary response is required then the column 504 is shownwith a “N”. This will be further described below.

For purposes of table 500, the first control valve 220 has a responseindicated with reference number 506, the second control valve 224 has aresponse indicated as reference number 510, the third control valve 228has a response indicated as reference number 508, the fourth controlvalve 232 has a response indicated as reference number 514, and thefifth control valve 236 has a response indicated as reference number512.

In the secondary actuator or cylinder table 502, the rows and columnsare similar to those in table 500. A first column 516 provides fordifferent responses or reactions required of the different actuators orcylinders. If no response is required, then the row is left blank undercolumn 516. If, however, a response is required, then the type ofresponse is provided. As is similar to table 402, each actuator is beingcharacterized as either being in its extended position “E” or itsretracted position “R” in table 502. In the event the actuator is notactuated, then neither an “E” or an “R” appears in the respective box.The response of the first and second actuators is represented byreference number 518. The response of the third actuator 132 isrepresented by reference number 522, the response of the fourth actuator138 is represented by reference number 520, the response of the fifthactuator 144 is represented by reference number 526, and the response ofthe sixth actuator 150 is represented by reference number 524 in FIG. 5.

Since the hydraulic control system 300 of FIG. 3 is a hybridparallel-series control, hydraulic fluid flows through the system 300from the innermost frame section (e.g., the main frame 102) to theoutermost frame section (e.g., the first outer frame 108 or the secondouter frame 110). Since the third flow path or return line 312 is onlyfluidly coupled to the first and second outer frames, the fluid can flowthrough the first flow path 308 or second flow path 310 until it worksits way into the return line 312 and returns to the fluid reservoir 304.As will be described, the control system 300 may require two responseswhen independently actuating the third or fourth actuator and raising orlowering either the first inner or second inner frame. This is becauseas fluid is provided to the third actuator 132, for example, to raise orlower the first inner frame 104, the resulting raising or loweringmovement of the first inner frame 104 induces a similar raising orlowering movement of the first outer frame 108 as well. Fluid that isused to actuate the third actuator 132 then flows to the fifth actuator144, and the fifth actuator 144 is actuated to allow the fluid to bereturned to the fluid reservoir via the third fluid path 312.Controlling the fifth actuator 144 therefore results in a secondaryaction or response to enable the entire frame to be balanced out andcontrolled at approximately the same height (or same tool depth).

The ECU 212 may have the control logic of FIGS. 4 and 5 stored in amemory unit thereof. A processor of the ECU 212 may then execute thecontrol logic as commanded by the operator. This logic may also be partof a software program or algorithm used by the ECU 212 when controllingthe frame height of the implement.

As described above, when the operator desires to raise or lower theentire frame or only the main frame 102, then there is no interaction bythe ECU 212 to control the control valves. This is the case when thefirst control valve 220 is normally or biased in its open position, andthe other control valves are biased in their normally closed position.If, however, in a different embodiment the first control valve 220 is anormally closed valve, then the ECU 212 would intervene andelectronically control the valve 220 to its open position.

In the primary valve table 400 of FIG. 4, it is shown that a command toraise or lower the entire frame requires the first control valveresponse 404 to be open “O” and the other control valves to be closed“C”. The same is true if the ECU 212 receives an instruction to raise orlower the main frame 102. Again, the first control valve response 404 isto be open and the other control valve responses are closed. Moreover,with respect to the cylinder response table 402, whenever the entireframe or a frame section is controlled in a raised movement, therespective actuator or actuators are controlled to their extendedposition, and if a lowering instruction is received then the actuator oractuators are controlled to their retracted positions. This is clearlyshown in table 402 of FIG. 4 where the responses of all six actuators isto extend when raising the entire frame and all six actuators retractwhen lowering the entire frame.

The same is true whenever a single frame section is raised or lowered.For example, when the first outer frame 108 is raised, the correspondingactuator response 422 is to extend. As shown in table 402, when thefirst outer frame 108 is lowered, the corresponding actuator response422 is to retract.

Example 1

In a first example of the present disclosure, the operator sets a targetdepth for the plurality of tools coupled to each frame section of theimplement to 3 inches. During operation, the first sensor 216 and secondsensor 218 detect the main frame 102 is at a depth of 3.5 inches. Uponcommunicating this to the ECU 212, the ECU 212 may compare the detecteddepth to the target depth. In some instances, a threshold may beestablished such that the detected depth has to be greater than athreshold amount different from the target depth before the ECU 212takes any corrective action. For this example, suppose the threshold is0.25 inches and thus the detected depth of 3.5 inches exceeds thethreshold amount.

In order to adjust the main frame 102 and raise it from 3.5 inches tothe target depth of 3.0 inches, the ECU 212 may be programmed based onthe logic of FIGS. 4 and 5. Here, in table 400 the first control valve220 needs to be in its open position and the other control valves intheir closed position. As described above, the first control valve 220is normally open and the other control valves are normally closed. Thus,there is no required action on behalf of the ECU 212 other than monitorthe first and second sensors until the first actuator 122 and secondactuator 124 are actuated to their extended positions to raise the mainframe 102. As shown in table 402, the other actuators are also actuatedto their extended positions when raising the main frame 102.

Once the main frame 102 is raised to the target depth of 3 inches, theECU 212 receives communications from the other sensors indicating thatboth inner frames and both outer frames have also been raised by 0.5inches to 2.5 inches. Thus, corrective action is required. This isfurther shown in FIG. 5 in column 504 where it indicates a correctiveresponse is required. According to table 502, the corrective response isto close the first control valve 220. In addition, the second controlvalve 224 and third control valve 228 may be opened to allow the thirdactuator 132 and fourth actuator 138 to be actuated to lower the firstand second inner frames. As described above, with the parallel hydrauliccontrol, by lowering the first inner frame 104 a resulting action is thefirst outer frame 108 also lowers by approximately the same amount.Moreover, by lowering the second inner frame 106, the second outer frame110 also lowers by approximately the same amount. Thus, each framesection is operably controlled to the target depth.

Example 2

In a second example, the operator may set the target depth to 3 inchesagain. During operation, the ECU receives a signal from the fifth sensor230 indicating that the first outer frame 108 is detected at 2.5 inchesdeep. If the threshold is 0.25 inches, the detected depth exceeds thethreshold and is not at the target depth. Thus, the ECU 212 can operablycontrol the hydraulic fluid from the fluid source 302 through the secondflow path 310 and to the fourth control valve 232. Moreover, based ontable 402, to lower the first outer frame 108 the appropriate valveresponse 412 is close the first control valve, maintain the secondcontrol valve 224, the third control valve 228, and the fifth controlvalve 236 in their closed positions, and open the fourth control valve232. According to table 402, the fifth actuator 144 is actuated to itsretracted position to operably control a lowering movement of the firstouter frame 108 to the target depth. Once the first outer frame 108reaches the target depth, the hydraulic fluid can return via the thirdflow path 312 to the fluid reservoir 304. In addition, as shown intables 500 and 502, there is no secondary corrective action required. Inthis example, each of the five frame sections should be set at thetarget depth.

Example 3

In a third example, the operator commands a target depth of 3 incheswith a threshold amount of 0.25 inches. In this example, suppose the ECUreceives a signal from the fourth sensor 226 indicating that the firstinner frame 106 is at a depth of 3.5 inches. Since the detected depth isnot at the target depth of 3 inches, and it is outside of the thresholdrange of 0.25 inches, the ECU 212 can execute the logic set forth intables 400, 402, 500, and 502 to raise the second inner frame 106 by 0.5inches.

According to table 400, to raise the second inner frame 106 requires aprimary valve response 406 of closing the first control valve 220,opening the third control valve 228, and maintaining the other controlvalves in their closed positions. By doing so, hydraulic fluid cannotflow through the first control valve 220 via the first flow path, andinstead flows through the second flow path 310. Fluid passes through thethird control valve 228 and the fourth actuator 138 may be actuated toits extended position as shown in table 402.

As the second inner frame 106 is raised to the target depth of 3 inches,table 502 indicates a secondary corrective action is necessary. In thiscase, by raising the second inner frame 106 by 0.5 inches, the secondouter frame 110 is also raised by 0.5 inches to 3.5 inches. Again, thisdetected depth is not the target depth and exceeds the threshold rangeof 0.25 inches. As such, the ECU 212 takes corrective action to lowerthe second outer frame 110. As shown in table 500, the correspondingresponse is to maintain the first control valve 220, the second controlvalve 224, and the fourth control valve 232 in their closed positions.In addition, the ECU 212 operably controls the third control valve 228from its open position to its closed position, and operably controls thefifth control valve 236 from its closed position to its open position.This allows fluid to flow through the fifth control valve 236 and to thesixth actuator 150. The sixth actuator can be actuated to lower thesecond outer frame 110 to the target depth of 3 inches, and fluid can bereturned to the fluid reservoir 304 via the third fluid path 312.

The above examples are provided only to illustrate how the ECU 212 maybe programmed to control the different control valves and actuators formoving the entire frame and each frame section as commanded by theoperator. It should be appreciated that in other embodiments, and asdescribed above, one or more of the control valves may be biased in adifferent position than as shown and described above. As such, the ECU212 may be programmed accordingly to raise or lower the frame or framesections utilizing the parallel-series hydraulic control system asdescribed herein.

Referring to FIG. 6, a different embodiment of an agricultural implement600 is shown. In this embodiment, reference numbers previously describedabove and shown in FIGS. 1-5 refer to the same features in FIG. 6. Thisimplement 600 is capable of performing a cultivating operation, althoughthe use or function of the implement is not limiting to this embodiment.The implement is shown being formed by a multiple sections or frame. Forinstance, a first or centrally located frame 602 is positioned towardsthe middle of the implement 600. A second frame 604 and a third frame606 are disposed on opposite sides of the main frame 602. Although onlythree frame sections are shown in FIG. 6, other embodiments may includemore than three sections. Alternatively, one or two frame sections arealso possible.

Similar to the previously described embodiments, the first frame section602 includes one or more frame members 608 that form the entire section602. Likewise, the second frame section 604 includes one or more framemembers 610, and the third frame section 606 includes one or more frame612. In at least one embodiment, front wheels 116 and rear wheels 614may be coupled to the frame members.

In the embodiment of FIG. 6, work tools 628 are provided for performinga work function (e.g., the cultivating operation). For purposes of thisdisclosure, any type of work tool may be used for performing a desiredfunction. In this embodiment, there are a plurality of tools 628provided for performing the work function. In a different embodiment,there may only be one work tool depending upon the type of work functionbeing executed. Here, the plurality of work tools 628 are coupled to asub-frame, and the sub-frame is coupled to one of the frame members ofeither the first frame 602, the second frame 604, or the third frame606.

In FIG. 6, a first sub-frame 616, a second sub-frame 618, a thirdsub-frame 620, a fourth sub-frame 620, a fifth sub-frame 620, and asixth sub-frame 620 are shown. There may be any number of sub-frames inother embodiments. Moreover, each sub-frame may be coupled at a locationbelow the main frame. For purposes of this embodiment, the first framesection 602, the second frame section 604, and the third frame section606 may be collectively referred to as a main frame. Thus, the pluralityof tools 628 are coupled to one of the sub-frames beneath the mainframe.

Each sub-frame may be pivotally coupled to the main frame via anactuator. As such, the respective sub-frame may be pivoted with respectto the main frame. In FIG. 6, the first sub-frame 616 is pivotallycontrolled and coupled to the first frame section 602 by a firstactuator 630. Similarly, the second sub-frame 618 may be pivotallycontrolled and coupled to the first frame section 602 by a secondactuator 630. Although not shown, the third sub-frame 620 and fifthsub-frame 624 may each be coupled by an independent actuator to thesecond frame section 604. Similarly, and also not shown, the fourthsub-frame 622 and the sixth sub-frame 626 may each be coupled by anindependent actuator to the third frame section 606.

Each of the aforementioned actuators may be a hydraulic actuator thatfunctions similarly to those described above and shown in FIGS. 1-3.Alternatively, other types of actuators may be used such as electricactuators, mechanical actuators, and any other known type of actuator.In the embodiment of FIG. 6, each actuator is a hydraulic actuatorcontrolled by hydraulic fluid. Moreover, each actuator includes acylinder (not shown) having a first end coupled to the main frame (e.g.,the respective frame section 602, 604, 606) with a rod (not shown) orother member that telescopically moves with respect to the cylinderbased on hydraulic pressure within the cylinder. The rod or other membermay be coupled to the respective sub-frame to allow pivotal movement ofthe sub-frame with respect to the main frame. The sub-frame can pivotwith respect to the main frame as the actuator is controlled between itsextended and retracted positions.

As the sub-frame pivots with respect to the main frame, the angle ofeach of the plurality of tools 628 coupled to the sub-frame changes withrespect to a direction of travel identified by arrow 634 in FIG. 6. Theimplement 600 may be driven along the direction of travel 634 by amachine or tractor, as described above. In one example, the angle ofeach tool 628 may be changed by 60° or less. In another example, theangle may be changed by 30° or less. In a further example, the angle maybe changed by 10° or less with respect to the direction of travel 634.In yet a further example, the angle of each tool 628 may be variedbetween 0-10° with respect to the direction of travel 634. Other anglesof variation are further contemplated in this disclosure, and may dependon the type of implement, tool, or work function.

The variable angle setting of each sub-frame may be controlled by theECU 212. This may be controlled hydraulically according to theembodiment shown in FIG. 3. Here, each sub-frame may be coupled to themain frame (e.g., the first frame section 602, the second frame section604, and third frame section 606) via an actuator. Hydraulic fluid canbe controlled to the different actuators in either a series or parallelcontrol. Thus, the variable angle control setting is handled in a mannersimilar to the depth control setting as previously described.

For sake of clarity, fluid flow may be directed to a control valvesimilar to that of the first control valve 220. If the ECU 212 controlsthe control valve to its open position, hydraulic fluid can flow in aseries path to each actuator for adjusting the angle of each sub-framerelative to the main frame. If, however, the ECU 212 only wants tocontrol the angle setting of one sub-frame, the ECU 212 may close thecontrol valve and open a different control similar to the other controlvalves (224, 228, 232, 236) described above. As such, a parallel flowpath is formed to enable hydraulic fluid to flow to the actuator thatcontrols pivotal movement of the desired sub-frame. A secondarycorrective action, similar to that described in Example 3 above, mayalso be required and achieved according to the same teachings andprinciples above. In addition, any of the control valves in thisembodiment may be normally open or closed, and the same principles applyfor achieving series-parallel hydraulic control of the implement.

Thus, the angle of any one sub-frame may be hydraulically controlled viaparallel control to a desired setting with respect to the direction oftravel 634. Moreover, all of the sub-frames can be angularly varied withrespect to the main frame via series control, as described above.

In a further embodiment, the depth in which a tool or plurality of tools628 coupled to a sub-frame may be controllably varied with respect to aground surface. In this embodiment, the sub-frame may be coupled to arock shaft that rotates or pivots in a substantially vertical direction.The rock shaft may also be coupled to one end of an actuator, whereasthe opposite end of the actuator is coupled to the main frame. In thisembodiment, the cylinder of the actuator is coupled to the main frame,and the cylinder rod is coupled to the rock shaft. As the cylinder rodextends and retracts with respect to the cylinder, the rock shaft isrotated. As the rock shaft rotates, the sub-frame moves up or down tochange the depth in which the tool or plurality of tools 628 penetratesinto the underlying ground surface.

Similar to the previously described embodiments, the ECU 212 can controla position of a control valve between an open and closed position. Inthe open position, hydraulic fluid can flow through a first flow paththrough the control valve to provide a series hydraulic control. Theseries hydraulic control allows hydraulic fluid to flow to each of aplurality of actuators for operably adjusting the depth of tools 628coupled to different sub-frames. In FIG. 6, for example, hydraulic fluidcan flow to the first actuator 630 and second actuator 632 in series sothat the plurality of tools 628 mounted to the first sub-frame 616 andsecond sub-frame 618 may be controllably adjusted to different depths.In FIG. 6, the aforementioned rock shafts are not shown, but in thisembodiment, a rock shaft would be coupled between the first actuator 630and the first sub-frame 616, and a different rock shaft would be coupledbetween the second actuator 632 and the second sub-frame 618. A similararrangement may be provided with respect to the third sub-frame 620, thefourth sub-frame 622, the fifth sub-frame 624, and the sixth sub-frame626.

If, however, only one of the sub-frames needs to be adjusted to meet adesired tool depth, then parallel control may be used to achieve thedesired depth. Here, the control valve may be closed so that hydraulicfluid does not pass therethrough. With the valve closed, fluid may flowthrough a parallel flow path similar to that shown in FIG. 3 andidentified as the second flow path 310. The ECU 212 may operably controla different control valve so that fluid may flow through that particularcontrol valve and to the actuator that is able to adjust the height ofthe respective sub-frame. In FIG. 6, for example, an actuator (notshown) may receive hydraulic fluid through the parallel flow path sothat the third sub-frame 620, the fourth sub-frame 622, the fifthsub-frame 624, or the sixth sub-frame 626 may be adjusted. As alsodescribed, depending upon which sub-frame is adjusted, a secondarycorrective action may be required in a similar manner as describedabove.

In an embodiment similar to the previous one, a tool or plurality oftools may be coupled directly to the rock shaft. In this embodiment,there may not be a sub-frame, but the tool or plurality of tools may beoperably controlled in a similar manner as previously described.

Referring to FIG. 7, an alternative embodiment of the agriculturalimplement 100 of FIG. 1 is shown in terms of an air seeder implement700. The air seeder implement 700 may be constructed similar to thefield cultivator of FIG. 1 such that it is designed to couple to a workmachine and perform a work function. For example, the air seederimplement 700 may include ground-engaging tools or openers for openingone or more furrows in the underlying soil for planting seed ordepositing fertilizer or other substances. The air seeder implement 700may be attached to a work machine or tractor (not shown) by a hitchassembly 712 such as a three-point hitch or a drawbar attachment. Thehitch assembly 712 includes a hitch frame member 714 that extendslongitudinally in a direction of travel for coupling to the work machineor tractor.

The air seeder implement 700 may include a transversely-extending framethat forms multiple frame sections. In FIG. 1, for example, theimplement 700 includes a main or center frame 702. The main frame 702 iscoupled to the hitch assembly 712 as shown. A first frame section orfirst inner frame 704 is disposed to one side of the main frame 702, anda second frame section or second inner frame 706 is disposed to anopposite side thereof. In addition, a third frame section or first outerframe 708 is disposed to an outside of the first inner frame 704, and afourth frame section or second outer frame 710 is disposed to an outsideof the second inner frame 706. Each frame section may be pivotablycoupled to the frame section adjacent thereto. The first inner frame704, for example, may be pivotably coupled to the main frame 702 and thefirst outer frame 708. Similarly, the second inner frame 706 may bepivotably coupled to the main frame 702 and the second outer frame 710.

The implement 700 may be supported by a plurality of wheels. Forexample, a pair of front wheels 716 are coupled to the frame at a frontend thereof. The main frame 702 may be supported by a first pair ofwheels 718 and a second pair of wheels 720. The first inner frame 704may be supported by wheels 730 and the second inner frame 106 may besupported by wheels 736. Likewise, the first outer frame 708 may besupported by wheels 742 and the second outer frame 710 may be supportedby wheels 748. While each section is shown being supported by adifferent pair of wheels, this is only shown in the illustratedembodiment. In other embodiments, there may be only a single wheelsupporting each frame section. In a different embodiment, there may bemore than a pair of wheels supporting each frame section. Moreover, theimplement 700 may include more than the front wheels 716. For instance,there may be back wheels disposed near the rear of the implement foradditional support.

In the illustrated embodiment of FIG. 7, the air seeder implement 700may include a plurality of actuators for controlling movement of theframe. Each actuator may be a hydraulic actuator, electric actuator, orany other known actuator. Moreover, each actuator may include an outerbody or cylinder in which a rod or piston moves between an extendedposition and a retracted position. In FIG. 7, the main frame 702includes a first actuator 722 and a second actuator 724. The first pairof wheels 718 may be coupled to the main frame 702 via a rock shaft (notshown) that may be hydraulically actuated by the first actuator 722. Thesecond pair of wheels 720 may be coupled to the main frame 702 viaanother rock shaft (not shown) that may be hydraulically actuated by thesecond actuator 724. The actuators can raise or lower the main frame 702relative to the wheels 718, 720, as will be described below.

The first inner frame 704 may include an actuator 732 for raising orlowering the first inner frame 704. Similarly, the second inner frame706 may include an actuator 738 for controlling a raising or loweringmovement of the second inner frame 704. The first outer frame 708 mayinclude an actuator 744 and the second outer frame 710 may include anactuator 750. The actuator 744 may control raising and lowering of thefirst outer frame 708 and the actuator 750 may control raising andlowering of the second outer frame 710.

In FIG. 7, the main frame 702 includes a plurality of main frame members726. A plurality of ground-engaging tools or openers 752 may be coupledto the main frame members 726 for engaging a ground surface or soil uponwhich the implement 700 travels. Similarly, the first inner frame 704includes a plurality of first inner frame members 728, the second innerframe 706 includes a plurality of second inner frame members 734, thefirst outer frame 708 includes a plurality of first outer frame members740, and the second outer frame 710 includes a plurality of second outerframe members 746. Each of these frame members may include a pluralityof ground-engaging tools or openers 752 coupled thereto.

While FIG. 7 represents an illustrated embodiment of an air seederimplement with five frame sections, this disclosure is not limited tothis embodiment. Other embodiments may include only three sections witha main frame and two outer frames. Alternatively, there may be more thanfive frame sections in further embodiments. Thus, this disclosure is notlimited to any number of frame sections, and the teachings herein may beapplicable to any multi-section implement.

Referring to FIG. 8, a side view of the air seeder implement 700 of FIG.7 is further illustrated. Here, the air seeder includes a frame 800which may form part of the second outer frame member 746. In any event,the wheels 748 may be coupled to the frame 800. The wheels 748 mayinclude a pair of wheels at the front of the implement 700 and a pair ofwheels at the rear thereof, as shown in FIG. 8.

In this view, the air seeder implement 700 may be configured as acombination seeder and fertilizing implement. In this configuration, theimplement 700 may include a plurality of ground-engaging tool or openerassemblies 752. In FIG. 8, for example, a first ground-engaging tool oropener assembly 802 is disposed at a front end of the implement 700, asecond ground-engaging tool or opener assembly 804 is disposed to therear of the first ground-engaging tool or opener assembly 802, and athird ground-engaging tool or opener assembly 806 is disposed at a rearof the implement 700. Each ground-engaging tool or opener assembly isshown including a furrow or trench opener 808. The furrow or trenchopener 808 may be configured as any furrow opener configured to engagethe soil and form a trench in it. Thus, its design for purposes of thisdisclosure may be any conventional furrow opener known in the art.

A seed distribution tube 810 may be coupled to or adjacently to the rearof the opener 808. In this manner, seed may be deposited into the furrowor trench formed by the opener 808. The ground-engaging tool or openerassembly may also include a second tube or distributor for depositingfertilizer or other substance into the furrow along with the seed. Oncethe seed and fertilizer has been distributed into the furrow or trench,a disk or wheel 814 may close the furrow or trench.

Other components may also be included with the air seeder implement 700.For instance, depth gauging wheels may be used to measure the depth ofthe furrow or trench to ensure that the seed is planted at theappropriate depth. Moreover, actuators, rockshafts, or other componentsfor adjusting the depth may be used as well. The actuators and controlsystem described in FIGS. 1-3 may be used with the air seeder implement700 for adjusting the depth of the ground-engaging openers. Further,while three ground-engaging tool or opener assemblies are shown in FIG.8, it is to be understood that any number of these assemblies may becoupled to the frame 800 to achieve the planting and fertilizingoperation.

While embodiments incorporating the principles of the present disclosurehave been described hereinabove, the present disclosure is not limitedto the described embodiments. Instead, this application is intended tocover any variations, uses, or adaptations of the disclosure using itsgeneral principles. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art to which this disclosure pertains and which fallwithin the limits of the appended claims.

1. An seeding implement, comprising: a transversely extending frameforming at least a first frame section, a second frame section, and athird frame section, where the first frame section is disposed betweenthe second and third frame sections; a hitch member configured to coupleto a work machine, the hitch member being coupled to at least one of thefirst, second, and third frame sections; and a first actuator and asecond actuator coupled to the first frame section, a third actuatorcoupled to the second frame section, and a fourth actuator coupled tothe third frame section; a fluid source for providing hydraulic fluid; afirst control valve operably controllable between an open position and aclosed position, the first control valve being fluidly coupled betweenthe fluid source and the first and second actuators; a second controlvalve operably controllable between an open position and a closedposition, the second control valve being fluidly coupled to the thirdactuator in its open position; a third control valve operablycontrollable between an open position and a closed position, the thirdcontrol valve being fluidly coupled to the fourth actuator in its openposition; a first flow path defined between the fluid source and thethird and fourth actuators, the first flow path fluidly coupling thefirst actuator, the second actuator, the third actuator, and the fourthactuator in series with one another when the first control valve is inits open position, the second control valve is in its closed position,and the third control valve is in its closed position; and a second flowpath defined between the fluid source and the third and fourthactuators, the second flow path fluidly coupling at least the third andfourth actuators in parallel with one another when the first controlvalve is in its closed position, and either the second control valve orthe third control valve is in its open position.
 2. The seedingimplement of claim 1, further comprising: a fluid reservoir; and a thirdflow path fluidly coupling the third actuator and the fourth actuator tothe fluid reservoir.
 3. The seeding implement of claim 1, wherein thehydraulic control system comprises: a first node fluidly coupling thefirst and second flow paths to one another; a second node fluidlycoupling the first control valve, the first actuator and the secondactuator to one another; a third node fluidly coupling the first fluidpath, the second fluid path, the second control valve and the thirdactuator to one another; and a fourth node fluidly coupling the firstfluid path, the second fluid path, the third control valve, and thefourth actuator to one another.
 4. The seeding implement of claim 1,further comprising: a first sub-frame coupled to and positioned belowthe first frame section, where the first actuator is coupled between thefirst frame section and the first sub-frame; a second sub-frame coupledto and positioned below the first frame section, where the secondactuator is coupled between the first frame section and the secondsub-frame; a third sub-frame coupled to and positioned below the secondframe section, where the third actuator is coupled between the secondframe section and the third sub-frame; a fourth sub-frame coupled to andpositioned below the third frame section, where the fourth actuator iscoupled between the third frame section and the fourth sub-frame; aplurality of ground-engaging tools coupled to each of the first, second,third, and fourth sub-frames; wherein: actuation of the first actuatoroperably pivots the first sub-frame relative to the first frame sectionfor adjusting an angle of the plurality of ground-engaging tools coupledto the first sub-frame; actuation of the second actuator operably pivotsthe second sub-frame relative to the first frame section for adjustingan angle of the plurality of ground-engaging tools coupled to the secondsub-frame; actuation of the third actuator operably pivots the thirdsub-frame relative to the second frame section; and actuation of thefourth actuator operably pivots the fourth sub-frame relative to thethird frame section.
 5. The seeding implement of claim 1, furthercomprising: a first sub-frame coupled to and positioned below the firstframe section, where the first actuator is coupled between the firstframe section and the first sub-frame; a second sub-frame coupled to andpositioned below the first frame section, where the second actuator iscoupled between the first frame section and the second sub-frame; athird sub-frame coupled to and positioned below the second framesection, where the third actuator is coupled between the second framesection and the third sub-frame; a fourth sub-frame coupled to andpositioned below the third frame section, where the fourth actuator iscoupled between the third frame section and the fourth sub-frame; aplurality of ground-engaging tools coupled to each of the first, second,third, and fourth sub-frames; wherein: actuation of the first actuatoroperably moves the first sub-frame relative to the first frame sectionfor adjusting a depth of the plurality of ground-engaging tools coupledto the first sub-frame; actuation of the second actuator operably movesthe second sub-frame relative to the first frame section for adjusting adepth of the plurality of ground-engaging tools coupled to the secondsub-frame; actuation of the third actuator operably moves the thirdsub-frame relative to the second frame section for adjusting a depth ofthe plurality of ground-engaging tools coupled to the third sub-frame;and actuation of the fourth actuator operably moves the fourth sub-framerelative to the third frame section for adjusting a depth of theplurality of ground-engaging tools coupled to the fourth sub-frame. 6.The seeding implement of claim 1, further comprising: an electroniccontrol unit coupled to the frame for controlling the first, second andthird control valves between their respective open and closed positionsa first sensor disposed in electrical communication with the electroniccontrol unit, the first sensor detecting a position of the first framesection; a second sensor disposed in electrical communication with theelectronic control unit, the second sensor detecting a position of thesecond frame section; and a third sensor disposed in electricalcommunication with the electronic control unit, the third sensordetecting a position of the third frame section.
 7. The seedingimplement of claim 6, wherein each frame section includes a plurality ofground-engaging tools for penetrating a soil upon which the implementtravels; further wherein, each of the first, second, and third sensoroperably detects a depth of penetration of the plurality ofground-engaging tools coupled to each frame section and communicates thedetected depth to the electronic control unit, the electronic controlunit compares the detected depth to a target depth and operably controlsthe position of each control valve until the depth of the plurality ofground-engaging tools on each frame section is at the target depth. 8.The seeding implement of claim 7, wherein, when the depth of theplurality of ground-engaging tools coupled to the second frame sectionor the third frame section is not at the target depth, the electroniccontrol unit operably controls fluid flow through the third or fourthactuator via the second flow path until the depth is detected at thetarget depth.
 9. The seeding implement of claim 5, further comprising: afourth frame section coupled to the second frame section, the fourthframe section including a fifth actuator for controlling a raising orlowering movement of the fourth frame section; a fifth frame sectioncoupled to the third frame section, the fifth frame section including asixth actuator for controlling a raising or lowering movement of thefifth frame section; a fourth control valve operably controllablebetween an open position and a closed position, the fourth control valvebeing fluidly coupled to the fifth actuator in its open position; and afifth control valve operably controllable between an open position and aclosed position, the fifth control valve being fluidly coupled to thesixth actuator in its open position; wherein, the first flow pathfluidly couples the first, second, third, fourth, fifth, and sixthactuators in series with one another when only the first control valveis in its open position, and the second flow path fluidly couples thethird, fourth, fifth, and sixth actuators in parallel with one anotherwhen the first control valve is in its closed position.
 10. The seedingimplement of claim 9, further comprising: a plurality of ground-engagingtools coupled to each frame section; and a plurality of sensors fordetecting a depth at which the plurality of ground-engaging toolscoupled to each frame section penetrates a soil upon which the implementtravels along; wherein, when the depth of the plurality ofground-engaging tools coupled to either the second frame section or thethird frame section is not at a target depth, the electronic controlunit operably controls the first control valve to its closed positionand either the second or third control valve to its open position sothat hydraulic fluid from the fluid source flows through the second flowpath to either the third or fourth actuator to raise or lower the secondor third frame section until the depth of the first frame section, thesecond frame section and the third frame section are at the targetdepth.
 11. The seeding implement of claim 10, wherein once the depth ofthe second frame second or the third frame section is operablycontrolled to the target depth, the electronic control unit operablycontrols the first control valve to remain in its closed position, thesecond and third control valves are controlled to their respectiveclosed positions, and either the fourth or fifth control valve isoperably controlled to its open position so that hydraulic fluid fromthe fluid source flows through the second flow path to either the fifthor sixth actuator to raise or lower the fourth or fifth frame sectionuntil the depth of the first frame section, the second frame section,the third frame section, the fourth frame section, and the fifth framesection are at the target depth.
 12. A work machine, comprising: aframe; a controller for controlling the machine; a fluid source forproviding hydraulic fluid; a seeding implement coupled to the frame forperforming a work function, the seeding implement including: atransversely extending frame forming at least a first frame section, asecond frame section, and a third frame section, where the first framesection is disposed between the second and third frame sections; aplurality of ground-engaging tools coupled to each of the first, second,and third frame sections; an electronic control system forelectronically controlling the implement, the electronic control systemincluding an electronic control unit (ECU) and a plurality of sensors,where the ECU is disposed in communication with the controller and theplurality of sensors are configured to detect a depth of penetration ofthe plurality of ground-engaging tools into a ground surface upon whichthe implement travels, each of the plurality of sensors disposed inelectrical communication with the ECU; and a hydraulic control systemfor hydraulically controlling a raising or lowering movement of eachframe section, the hydraulic control system including: a first actuatorcoupled to the first frame section, a second actuator coupled to thesecond frame section, and a third actuator coupled to the third framesection; a first control valve operably controllable between an openposition and a closed position, the first control valve being fluidlycoupled between the fluid source and the first actuator; a secondcontrol valve operably controllable between an open position and aclosed position, the second control valve being fluidly coupled to thesecond actuator in its open position; a third control valve operablycontrollable between an open position and a closed position, the thirdcontrol valve being fluidly coupled to the third actuator in its openposition; a first flow path defined between the fluid source and thesecond and third actuators, the first flow path fluidly coupling thefirst actuator, the second actuator, and the third actuator in serieswith one another when the first control valve is in its open position,the second control valve is in its closed position, and the thirdcontrol valve is in its closed position; and a second flow path definedbetween the fluid source and the second and third actuators, the secondflow path fluidly coupling at least the second and third actuators inparallel with one another when the first control valve is in its closedposition, and either the second control valve or the third control valveis in its open position.
 13. The work machine of claim 12, furthercomprising: a fluid reservoir fluidly coupled to the fluid source; and athird flow path fluidly coupling the second actuator and the thirdactuator to the fluid reservoir.
 14. The work machine of claim 12,further comprising: a fourth frame section coupled to the second framesection, the fourth frame section including a fourth actuator forcontrolling a raising or lowering movement of the fourth frame section;and a fifth frame section coupled to the third frame section, the fifthframe section including a fifth actuator for controlling a raising orlowering movement of the fifth frame section; a fourth control valveoperably controllable by the ECU between an open position and a closedposition, the fourth control valve being fluidly coupled to the fourthactuator in its open position; and a fifth control valve operablycontrollable by the ECU between an open position and a closed position,the fifth control valve being fluidly coupled to the fifth actuator inits open position; wherein, the first flow path fluidly couples thefirst, second, third, fourth, and fifth actuators in series with oneanother when only the first control valve is in its open position, andthe second flow path fluidly couples the second, third, fourth, andfifth actuators in parallel with one another when the first controlvalve is in its closed position.
 15. A method for controlling a seedingimplement having a transversely extending frame forming a center framesection, a first frame section disposed on one side of the center framesection, and a second frame section disposed on an opposite side of thecenter frame section, the method comprising: providing a fluid source,an electronic control unit, a first control valve, a second controlvalve, a third control valve, a first and a second actuator coupled tothe center frame section, a third actuator coupled to the first framesection, a fourth actuator coupled to the second frame section, and aplurality of ground-engaging tools coupled to each frame section;providing a first fluid path and a second fluid path, the first fluidpath fluidly coupling the first, second, third and fourth actuators inseries when the first control valve is open, and the second fluid pathfluidly coupling the third and fourth actuators in parallel with oneanother when the first control valve is closed; operating the seedingimplement in a working position, where in the working position each ofthe plurality of ground-engaging tools is disposed at a target depth ina ground surface upon which the implement travels; detecting a depthposition of the plurality of ground-engaging tools coupled to the centerframe section with a first sensor, a depth position of the plurality ofground-engaging tools coupled to the first frame section with a secondsensor, and a depth position of the plurality of ground-engaging toolscoupled to the second frame section with a third sensor; communicatingthe depth position of the plurality of ground-engaging tools to theelectronic control unit; determining if the depth position of theplurality of ground-engaging tools is at the target depth; wherein, whenthe depth position of the plurality of ground-engaging tools coupled tothe center frame section, the first frame section, or the second framesection is not at the target depth, the method further comprises:controllably opening the first control valve and closing the second andthird control valves to raise or lower the center frame section untilthe depth of the plurality of ground-engaging tools coupled to thecenter frame section is at the target depth; and controllably closingthe first control valve and opening the second or third control valve toraise or lower either the first or section frame section until the depthof the plurality of ground-engaging tools coupled to the first or secondframe section is at the target depth.
 16. The method of claim 15,further comprising controlling fluid flow through the first fluid pathto raise or lower the center frame section, the first frame section andthe second frame section.
 17. The method of claim 15, further comprisingcontrolling fluid flow through the first and second actuators toposition the frame between a transport position and its workingposition.
 18. The method of claim 15, further comprising: controllingfluid flow through the second fluid path to control the depth of theplurality of ground-engaging tools coupled to one of the first or secondframe sections; and blocking fluid flow through the first flow path tothe first and second actuators.
 19. The method of claim 15, furthercomprising: providing a third frame section coupled to the first framesection, a fourth frame section coupled to the second frame section, afourth control valve, a fifth control valve, a fifth actuator, and asixth actuator, where the fifth actuator and sixth actuator are fluidlycoupled in series to the first actuator, second actuator, third actuatorand fourth actuator via the first flow path, and the fifth actuator andsixth actuator are fluidly coupled in parallel with the third actuatorand the fourth actuator via the second flow path; providing a pluralityof ground-engaging tools coupled to the third frame section and thefourth frame section; detecting the plurality of ground-engaging toolscoupled to either the third frame section or the fourth frame section isnot at the target depth; controllably closing the first control valveand the first flow path; controllably opening the fourth or the fifthcontrol valve; and fluidly coupling the fluid source to the fifth orsixth actuator to raise or lower the third frame section or the fourthframe section until the plurality of ground-engaging tools coupled tothe third frame section and fourth frame section are at the targetdepth.
 20. The method of claim 15, further comprising: providing a thirdframe section coupled to the first frame section, a fourth frame sectioncoupled to the second frame section, a fourth control valve, a fifthcontrol valve, a fifth actuator, and a sixth actuator, where the fifthactuator and sixth actuator are fluidly coupled in series to the firstactuator, second actuator, third actuator and fourth actuator via thefirst flow path, and the fifth actuator and sixth actuator are fluidlycoupled in parallel with the third actuator and the fourth actuator viathe second flow path; providing a plurality of ground-engaging toolscoupled to the third frame section and the fourth frame section;detecting the plurality of ground-engaging tools coupled to the firstframe section or the second frame section is not at the target depth;controllably closing the first control valve; controllably opening thesecond control valve or the third control valve depending upon whetherthe depth of the plurality of ground-engaging tools coupled to the firstor second frame sections is not at the target depth; fluidly couplingthe fluid source to the third actuator or the fourth actuator to raiseor lower the first or the second frame section until the plurality ofground-engaging tools coupled to the first and second frame sections areat the target depth; further detecting the depth of the plurality ofground-engaging tools coupled to either the third frame section or thefourth frame section is not at the target depth; controllablymaintaining the first control valve in its closed position; controllablyclosing the second or third control valve; controllably opening thefourth or fifth control valve; and fluidly coupling the fluid source tothe fifth or sixth actuator to raise or lower the third frame section orthe fourth frame section until the plurality of ground-engaging toolscoupled to the third frame section and fourth frame section are at thetarget depth.